On interactive graph paper, sketch straight lines by clicking the pencil icon — or curved ones by selecting the fountain pen nib — then login to calculate the area and perimeter of the shapes constructed. The gear icon in the upper-right corner lets you import an image or PDF over the grid lines. Tracing over a Google Map sets the scale of the drawing canvas automatically, but SketchAndCalc™ also allows for toggling scale and units and keyboard input of lengths.